Electric ballast



July 26, 1949. :R. F. ROWE 2,477,132

ELECTRIC BALLAST Filed Dec. 22, 1945 I I 2 Sheets-Sheet 1 Inventor;

Robert F Rowe,

His Attdr-ney.

R. F. ROWE ELECTRIC BALLAST Jyly 26, 1949.

2 Sheets-Sheet 2 Filed Dec. 22, 1945 Inventor: Rober-t E Rowe,

His Attorney.

Patented July 26,1949

ELECTRIC BALLAST Robert F. Rowe, Fort Wayne, Ind., assignor to General Electric Company, a corporation of New York Application December 22, 1945, Serial No. 637,027

2 Claims. 1

This invention relates to electric ballasts and more particularly to improvements in ballasts for fluorescent lamps.

Fluorescent lamps, being electric discharge devices with a negative resistance characteristic, require a ballast in their circuits. There are a Wide variety of styles of fluorescent lamps and an even greater variety of fixtures for supporting such lamps. A form of fluorescent lamp which it is expected will be used in large numbers consists of a circular arrangement of the fluorescent lamp tube so that its two ends, each of which ordinarily contains a filament, are close together and can be fitted into the same socket. Such a circular lamp may be used in ceiling fixtures or wall fixtures or in portable lamps of either the floor or table variety. One of the problems associated with such lamps and lamp fixtures is the construction of as nearly a universal ballast as is possible. By universal ballast is meant a ballast which can be used easily, simply and inexpensively in any and al1 types of fixtures for either exposed or concealed mountings.

In accordance with this invention there is provided a universal ballast which is characterized by a smooth, attractive, unbroken exterior surface which has no mounting feet or lugs. Provision for mounting this ballast consists of a straight opening or hole which passes entirely through it from one side to the other. This hole is of suflicient diameter to receive an ordinary standard three-eighths inch threaded pipe such as is commonly used in house wiring for conduit and supporting purposes and which fits the threads on standard house wiring devices, such as outlet boxes and the various kinds of adapters. The ballast is also disk-shaped so that it will fit readily into the base of floor and table lamps and can also be used easily in wall and ceiling fixtures. Furthermore, in many cases it can be mounted inside the circular lamp tube so as to provide a very compact installation.

An object of the invention is to provide a new and improved electric ballast.

Another object of the invention is to provide a new and improved combination of ballast and lamp fixture.

A further object of the invention is to provide a new and improved fluorescent lamp construction.

The invention will be better understood from the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

In the drawing Fig. 1 is a perspective view of a preferred form of ballast constructed in accordance with this invention, Fig. 2 is a sectional view of the ballast housing, Fig. 3 is an exploded view of the ballast housing, Fig. 4 is a phantom view of one suitable interior arrangement of the ballast, Fig. 5 is a floor lamp with the ballast mounted in its base, Fig. 6 is a circuit diagram showing how a ballast having the elements shown in Fig. 4 may be connected to a supply line and a single lamp, and Fig. '7 is a ceiling or wall fixture with the ballast mounted therein.

Referring now to the drawing and more particularly to Fig. 1, the ballast is shown as a diskshaped housing I consisting of two principal parts which are a relatively deep circular panshaped casing member 2 and a circular flanged base member 3. Passing entirely through the ballast from one flat side to the other is a central mounting hole 4. The bottom of the casing is also provided with a smaller hole 5 through which extend three leads 6, I and 8 for the electrical elements of the ballast.

As shown in Fig. 2, the relatively small opening 5 is extruded inwardly and the extruded portions are turned over so as to form a smooth eyelet 9 for the leads. It will also be seen that the central openings, in the bottom of the casing 2 and in the base 3, are surrounded by indented portions l0 and II respectively. A tubular eyelet |2 is passed through the central opening in the bottom of the cover 2 and this eyelet is provided with an outwardly turned flange I3 which fits into the indented portion It) so as to be flush with the outer surface of the casing 2. The other end of the tubular eyelet I2 is long enough so that it can be spun over or turned over to form a flange 14 which lies in the indented portion ll so as to form a flush clamping or locking means for holding the base 3 securely to the casing 2.

If desired, a tubular spacer l5 may be slipped over the shank of the eyelet l2 so as to provide the proper spacing between the bottom of the casing and the base 3. However, when the housing is filled with insulating compound it usually is not necessary to have the spacer [5.

Fig. 3 clearly shows the four major parts 2, 3, I2 and i5 axially aligned and separated for showing how they may be assembled. The flange 13 of the eyelet l2 may be provided with small projections 16 on its inner surface by means of which the flange [3 can be projection welded to the indentation It in the bottom of the casing 2. After the eyelet l2 has been put into place the spacer l5, if used, may he slipped into place comprise a shell-type core 23 with a winding 2| on its central winding leg.

The remaining spaces in the ballast not occupied by' the above-described electrical parts are preferably filled with insulating compound. This securely anchors the electrical parts in place and makes the ballast strong enough to resist large clamping forces between its opposite sides.

One of many practical applications of my improved ballast is shown in Fig. 5, which illustrates a portable floor lamp consisting essentially of the usual base 22, stem 23, and shade 24. Mounted on a suitable holder 25 near the top of the stem '23 is a circular fluorescent lamp 28.

' The stem 23 is conventionally threaded into the base 22 and it is shown as extending sufiiciently into the base so that itmay extend through the central opening 4 in the ballast l which has been 's'lidover it with its base Sagainst the underside of the base 22 ofthe lamp. Anut'Zl is threaded onto the'end of the stem 23 for securely clamping theballast i in place. A line lead. 28 extends through a suitable opening in the side of the base 22 and its conduetorsare connected to the Wire leads of the ballastand to a number of leads 2Q which extend up through the stem 23 which is, of course, hollow and thus acts both as a support and as a conduit for the leads '29. .The electrical parts shown in Figs. 4 and 5 may "ac'tuallybe connected as shown inFig. 6 in which the'three coils Ill, 59 and 21 are connected in series, the coil I8 being'the primary winding of the autotransformer to whose terminals the conductors of the input lead 28 are connected. The lamp 26 and reactor 21 are connected in series across the secondary winding of the autotransformer, that is tosay, across the coils I8 and i9 inseries with each other.

h As shown in Fig. '7, the invention is also very well adapted for use in ceiling and wall fixtures, especially fixtures for circular fluorescent lamps. While Fig, 7 illustrates a ceiling fixture, it will be "obvious that by rotating the drawing ninety degreesfit also illustrates a wall fixture. In this figure, an incoming conduit 36 extends through a conventional ceiling'cr wall iii. A backing nut 32 is screwed on the conduit flush with the ceiling or wall leaving the conduit extending a short distance beyond the backing nut. A ceiling or wall plate" 33 is then placed over the conduit and the ballast l is then slipped over the conduit and a Ioc'knut 34 is screwed on to the conduit and tight- "erred so 'asto hold the plate and ballast firmly to the ceiling or wall. (Bonnections are then made to the incoming'conduit wires, the ballast wires and the wires from a lamp holder'35. A housing 36 which carries the lamp holder 35 and a starter Socket 3?, already attached and wired, and a starter 33 inserted in the starter socket 37, is then mounted and held in place with screws which attac'hfit to the plate 33 a circular fluorescent lamp 3.! can then be inserted in the holder.

. Here again it will beseen that the ballast l is very .ea'sily attached to the fixture without any gseparatelmounting means other than the means 4 which holds the fixture itself in place and that it conforms to the general shape of the fixture and requires but a minimum increase in the dimension of the fixture in any direction.

While there have been shown and described particular embodiments of this invention, it will be obvious to those skilled in the art that various changes and modifications can be made therein without departing from the invention and, therefore, it is aimed in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A ballast housing for electric discharge devices comprising, in combination, a relatively deep pan-shaped casing of circular cross section, a pair of openings in the bottom of said panshaped casing, one of said openings being concentric with the circular cross section of said casing and being concentrically surrounded by an indented portion of the bottom of said casing, the other of said openings being relatively small, electrical apparatus in said housing having Wire leads extending through the smaller of said openings, a cylindrical eyelet passed through the central opening in the bottom of said casing, said eyelet having a flange which is on one end thereof and which'lies in said indented portion of the bottom of said casing so as to be flush with the outside surface of the bottom of said casing, said eyelet extending into said casing a distance sli htly greater than the height of said casing, and a circular base member having a flanged edge for engaging the sides of said casing member and having a centrally located opening for receiving the other end of said eyelet, the area of said base member surrounding its centrally located opening being indented, said other endof the eyelet being rolled over to form a flange which lies in the indented portion of said base member so as to be fiush with the outer surface of said base member for permanently fastening said casing and base members together.

2. A ballast housing for electric discharge devices comprising, in combination, a relatively deep pan-shaped casing of circular cross section, a pair of openings in the bottom of .saidpanshaped casing, one of said openingsflbeing concentric with the circular cross section of said casing and being concentrically surrounded by an indented portion of the bottom of said casing, the

other of said openings being relatively small, electrical apparatus in said housing having wire leads extending through the smaller of said openings, a cylindrical eyelet passed through the central opening in the bottom of said casing, said eyelet having a flange which is on one end thereof and which lies in said indented'portion of the bottom of said casing so as to be flush with the outside surface ofthe bottom of said casing, said eyelet extending into said casing a distance slightly greater than the height of said casing, a cylindrical spacer sleevefitted over said eyelet, said spacer sleeve being shorter than said eyelet, and a circular base member having a fianged'edge'for engaging the sides of said casing member and having a centrally located opening for receiving the other end of said eyelet, the area of said base member surrounding its centrally located opening being indented, said other end. of said eyelet being rolled over to form a flange which lies in the indented portion of said-base member so as to be flush with the outer surface of said.

ROBERT F. ROWE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Harvey May 31, 11921 Number 6 Name Date Mensing June 21, 1927 Grunow Feb. 12, 1929 De Lancey Mar. 8, 1932 Hays Sept. 19, 1933 Sclater Apr. 3, 1934 McDermott Oct. 22, 1935 Miller Oct. 13, 1942 Bardsley June 15, 1943 Johns June 6, 1944 Omansky Sept. 25, 1945 

